<?php

function is_utf8($content) {
	
	if(is_string($content)){
		
		// From http://w3.org/International/questions/qa-forms-utf-8.html
		return preg_match('/(
                [\xC2-\xDF][\x80-\xBF]            	# non-overlong 2-byte
            |    \xE0[\xA0-\xBF][\x80-\xBF]        	# excluding overlongs
            |    [\xE1-\xEC\xEE\xEF][\x80-\xBF]{2}  # straight 3-byte
            |    \xED[\x80-\x9F][\x80-\xBF]        	# excluding surrogates
            |    \xF0[\x90-\xBF][\x80-\xBF]{2}      # planes 1-3
            |    [\xF1-\xF3][\x80-\xBF]{3}        	# planes 4-15
            |    \xF4[\x80-\x8F][\x80-\xBF]{2}      # plane 16
            )/x', $content);
				 
	}
	else{
		return true;
	}
}

?>